I think it's an ideologically good idea, but practically it's not. Those are very technical products. Sure, to increase revenue you should have different revenue streams, but first, you cannot go and sell mortgages and insurance and things such as that if you're not trained and qualified; and secondly, you would then be taking away business from the private sector.
In answer to your question, sure, diversify and look for other income streams, but not at the expense of the private sector.